Just for people who didn't watch the video. They could only fit 12 bits in that they determined to be "optimal size" handle by making them half-size. But they disliked the idea of locking people into their bits, and changed the design so that a little rotation can adapt the storage area to 6 standard-sized bits.

Here is a link to the relevant section https://www.youtube.com/watch?v=2K5Gqp1cEcM&t=819s